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Plaat-plant Interactions And Arbuscular Mycorrhizal Fungi

Posted on:2012-10-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:1110330371969221Subject:Ecology
Abstract/Summary:PDF Full Text Request
Plant-plant interactions are important process in plant ecology. Direction (positive or negative) and strength of plant interactions are affected by environmental factors. How abiotic factors affect plant interactions has been well documented. However, whether and how biotic factors such as arbuscular mycorrhizal fungi (AMF) affect plant interactions remains elucidation. The present dissertation explored how AMF influence plant interactions and tried to answer the following questions:(1) Do AMF influence plant self-thinning through increasing plant competition? How does abiotic stress affect the role of AMF?(2) Do AMF enhance negative plant neighbor effect? How does abiotic stress affect the role of AMF?(3) What is the role of AMF-host preference in influencing plant intra-specific and inter-specific interactions? Combining field experiment, controlled experiment in greenhouse and meta-analysis, we got the following results:1Effects of AMF on plant self-thinningUnder no salinity treatment, AMF increased plant size of Medicago saliva L. thus increased intra-specific competition, and further changed self-thinning trajectory. AMF induced greater plant mortality during self-thinning. With salinity stress, AMF can also promote growth of Medicago saliva L., but did not influence plant competition and slope of self-thinning line. AMF decreased mortality and increased survival rate during self-thinning under salinity stress conditions.2Effect of AMF on plant neighbor effectControlled experiment in greenhouse showed that AMF increased plant competition between equal-aged individuals of Medicago saliva L. under no salinity treatment. With increasing salinity, mycorrhizal effect was not significant. Multi-factors meta-analysis showed that AMF driven positive effect of established plants on seedling growth under stressed condition, and this effect was not significant when there is no stress. Neighbor removal experiment in field showed that AMF driven the positive neighbor effect of established individuals of Tamarix chinensis Lour, on seedling growth in the high salinity conditions, but enhanced the competitive effect of established Tamarix chinensis hour, individuals on seedling growth.3Effect of AMF-host preference on plant interactionsResults showed that AMF-host preference existed in the preferred host plants and AM fungi in our studies. This preference influenced plant self-thinning in the mono-cultured plant populations, and inter-specific competition in mixture of two plants. For self-thinning populations of Medicago sativa L., the fungus G. diaphanum promotes plant growth most and induces the greatest self-thinning extent. For the inter-specific competition between Solidago canadensis L. and Kummerowia striata (Thund.) Schindl., the mycorrhizal fungus G. geosporum promotes Solidago canadensis L. growth most and not so beneficial to Kummerowia striata (Thund.) Schindl.. Solidago canadensish. promotes G. geosporum growth better than the host plant Kummerowia striata (Thund.) Schindl.. This preference enhanced the competitive exclusion of Solidago canadensis L. on Kummerowia striata (Thund.) Schindl..
Keywords/Search Tags:AMF-Host preference, Arbuscular Mycorrhizal Fungi, Competition, Kummerowia striata (Thun.) Schindl, Medicago sativa L., Multu-factorsmeta-anaIysis, Neighbor effect, Plant-plant interactions, Positive interactions, Salintystress, Self-thinning dynamics
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